{- |
Module : System.Log.Handler.Log4jXML
Copyright : Copyright (C) 2007-2011 John Goerzen
License : BSD3
Maintainer : bjorn.buckwalter@gmail.com
Stability : experimental
Portability: GHC only?
log4j[1] XMLLayout log handlers.
Written by Bjorn Buckwalter, bjorn.buckwalter\@gmail.com
-}moduleSystem.Log.Handler.Log4jXML(-- * Introduction{- | This module provides handlers for hslogger that are
compatible with log4j's XMLLayout. In particular log messages
created by the handlers can be published directly to the GUI-based
log viewer Chainsaw v2[2].
The set of log levels in hslogger is richer than the basic set
of log4j levels. Two sets of handlers are provided with hslogger4j,
one which produces logs with hslogger's levels and one which
\"demotes\" them to the basic log4j levels. If full hslogger
levels are used some Java installation (see below) is necessary
to make Chainsaw aware of them.
Usage of the handlers in hslogger4j is analoguous to usage of
the 'System.Log.Handler.Simple.StreamHandler' and
'System.Log.Handler.Simple.FileHandler' in "System.Log.Handler.Simple".
The following handlers are provided: -}-- ** Handlers with hslogger levels log4jStreamHandler,log4jFileHandler,-- ** Handlers with log4j levelslog4jStreamHandler',log4jFileHandler'-- * Java install process{- | This is only necessary if you want to use the hslogger levels.
Add @hslogger4j.jar@ from @contrib\/java@ to your classpath.
To use you will also need to have the jars @log4j-1.3alpha-7.jar@
and @log4j-xml-1.3alpha-7.jar@ that are distributed with Chainsaw
on your classpath.
(On Mac OS X I added all three jars to @~\/Library\/Java\/Extensions@.
It seems that it is not sufficient that Chainsaw already includes
its jars in the classpath when launching - perhaps the plugin
classloader does not inherit Chainsaw's classpath. Adding the
jars to @~\/.chainsaw\/plugins@ wouldn't work either.)
If for whatever reason you have to rebuild the hslogger4j jar
just run @ant@[3] in the @contrib\/java@ directory. The new jar
will be created in the @contrib\/java\/dist@ directory. The Java
source code is copyright The Apache Software Foundation and
licensed under the Apache Licence version 2.0. -}-- * Chainsaw setup{- | If you are only using the basic log4j levels just use
Chainsaw's regular facilities to browse logs or listen for log
messages (e.g. @XMLSocketReceiver@).
If you want to use the hslogger levels the easiest way to set
up Chainsaw is to load the plugins in @hslogger4j-plugins.xml@
in @contrib\/java@ when launching Chainsaw. Two receivers will
be defined, one that listens for logmessages and one for reading
log files. Edit the properties of those receivers as needed
(e.g. @port@, @fileURL@) and restart them. You will also want
to modify Chainsaw's formatting preferences to display levels
as text instead of icons. -}-- * Example usage{- | In the IO monad:
> lh2 <- log4jFileHandler "log.xml" DEBUG
> updateGlobalLogger rootLoggerName (addHandler lh2)
> h <- connectTo "localhost" (PortNumber 4448)
> lh <- log4jStreamHandler h NOTICE
> updateGlobalLogger rootLoggerName (addHandler lh)
-}-- * References{- |
(1) <http://logging.apache.org/log4j/>
(2) <http://logging.apache.org/chainsaw/>
(3) <http://ant.apache.org/>
-})whereimportControl.Concurrent(ThreadId,myThreadId)-- myThreadId is GHC only!importControl.Concurrent.MVarimportData.List(isPrefixOf)importSystem.IOimportSystem.Locale(defaultTimeLocale)importData.TimeimportSystem.LogimportSystem.Log.HandlerimportSystem.Log.Handler.Simple(streamHandler,GenericHandler(..))-- Handler that logs to a handle rendering message priorities according-- to the supplied function.log4jHandler::(Priority->String)->Handle->Priority->IO(GenericHandlerHandle)log4jHandlershowPriohpri=dohndlr<-streamHandlerhprireturn$setFormatterhndlrxmlFormatterwhere-- A Log Formatter that creates an XML element representing a log4j event/message.xmlFormatter::a->(Priority,String)->String->IOStringxmlFormatter_(prio,msg)logger=dotime<-getCurrentTimethread<-myThreadIdreturn.show$Elem"log4j:event"[("logger",logger),("timestamp",millistime),("level",showPrioprio),("thread",showthread)](Just$Elem"log4j:message"[](Just$CDATAmsg))where-- This is an ugly hack to get a unix epoch with milliseconds.-- The use of "take 3" causes the milliseconds to always be-- rounded downwards, which I suppose may be the expected-- behaviour for time.millist=formatTimedefaultTimeLocale"%s"t++(take3$formatTimedefaultTimeLocale"%q"t)-- | Create a stream log handler that uses hslogger priorities.log4jStreamHandler::Handle->Priority->IO(GenericHandlerHandle)log4jStreamHandler=log4jHandlershow{- | Create a stream log handler that uses log4j levels (priorities). The
priorities of messages are shoehorned into log4j levels as follows:
@
DEBUG -> DEBUG
INFO, NOTICE -> INFO
WARNING -> WARN
ERROR, CRITICAL, ALERT -> ERROR
EMERGENCY -> FATAL
@
This is useful when the log will only be consumed by log4j tools and
you don't want to go out of your way transforming the log or configuring
the tools. -}log4jStreamHandler'::Handle->Priority->IO(GenericHandlerHandle)log4jStreamHandler'=log4jHandlershow'whereshow'::Priority->Stringshow'NOTICE="INFO"show'WARNING="WARN"show'CRITICAL="ERROR"show'ALERT="ERROR"show'EMERGENCY="FATAL"show'p=showp-- Identical for DEBUG, INFO, ERROR.-- | Create a file log handler that uses hslogger priorities.log4jFileHandler::FilePath->Priority->IO(GenericHandlerHandle)log4jFileHandlerfppri=doh<-openFilefpAppendModesh<-log4jStreamHandlerhprireturn(sh{closeFunc=hClose}){- | Create a file log handler that uses log4j levels (see
'log4jStreamHandler'' for mappings). -}log4jFileHandler'::FilePath->Priority->IO(GenericHandlerHandle)log4jFileHandler'fppri=doh<-openFilefpAppendModesh<-log4jStreamHandler'hprireturn(sh{closeFunc=hClose})-- A type for building and showing XML elements. Could use a fancy XML-- library but am reluctant to introduce dependencies.dataXML=ElemString[(String,String)](MaybeXML)|CDATAStringinstanceShowXMLwhereshow(CDATAs)="<![CDATA["++escapeCDATAs++"]]>"whereescapeCDATA=replace"]]>""]]&lt;"-- The best we can do, I guess.show(Elemnameattrschild)="<"++name++showAttrsattrs++showChildchildwhereshowAttrs[]=""showAttrs((k,v):as)=" "++k++"=\""++escapeAttrv++"\""++showAttrsaswhereescapeAttr=replace"\"""&quot;".replace"<""&lt;".replace"&""&amp;"showChildNothing="/>"showChild(Justc)=">"++showc++"</"++name++">"-- Replaces instances of first list by second list in third list.-- Definition blatantly stoled from jethr0's comment at-- http://bluebones.net/2007/01/replace-in-haskell/. Can be swapped-- with definition (or import) from MissingH.replace::Eqa=>[a]->[a]->[a]->[a]replace__[]=[]replacefromtoxs@(a:as)=ifisPrefixOffromxsthento++drop(lengthfrom)xselsea:replacefromtoas